1. Field of the Invention
The invention relates to a node information management system and nodes which are suitable for various networks as well as a packet exchange network.
2. Related Background Art
A collecting method of node information in a conventional packet exchange network will be described.
Generally, nodes such as exchanges, routers, or the like and a monitoring apparatus for managing them are included in a network.
In order to monitor communication quality information such as delay of a packet, loss of the packet, traffic amount, band, and the like, setting information in nodes such as a transfer processing method of a routine table provided every node or the packet, and the like, and information regarding the user such as connecting time of each user, charging, and the like, etc., each node has a function for obtaining those information and managing them by a memory device of each node. In the following description, those communication quality information, node setting information, and information regarding the user are called node information.
As such a monitoring apparatus provided for the network, there is an apparatus called NMS (Network Management Station) for managing the node information. The NMS collects the node information by communication with each node by using a protocol such as SNMP (Simple Network Management Protocol), ICMP (Internet Control Message Protocol), or the like.
AS a node information collecting method of the NMS, for example, there are a polling method/trapping method using the SNMP and an active program method. The polling method and the trapping method have been disclosed in the prior art of the following literature 1. The active program method has been disclosed in the following literature 2 as a network management system using an active network technique.
Literature 1: JP-A-2000-047961
Literature 2: Suzuki et al., “Network Management Method with Active Network Technology”, The Institute of Electronics Information and Communication Engineers of Japan, Singaku Giho, Vol. 100, No. 178, Jul. 14, 2000.
The polling method is a method of starting the collection of the node information at an opportunity of the NMS itself. According to the trapping method, when a state of the node is changed, the node transmits a signal of an event opportunity called a trap to the NMS, thereby allowing the NMS to collect the node information.
The active program method has a feature such that a packet called a programmable packet circulates through each node. A program for a process to be instructed from the NMS to the node has been inserted in the programmable packet. When the programmable packet is received, each node executes the program. The programmable packet circulates through each node and brings back a program execution result of each node to the NMS.
In case of collecting the node information by the trapping method, there are the following problems. For example, if the trap cannot be transmitted to the NMS because a failure occurred in the node, the NMS is not able to know the failure or state of the node. Therefore, the polling method and active program method is generally and widely used.
However, the polling method and active program method also have the following problems. In the polling method, each node has to hold the node information for a period of time from timing when the node information is collected to the NMS to timing when the next node information is collected. Therefore, when a failure occurs in the node, the node information held in the node can be lost. In a manner similar to the above, also in the active program method, when a failure occurs in the node, the node information held in the node can be lost.
To avoid such problems, in the polling method and active program method, there is a method whereby the NMS executes the collection of the node information at a short period.
In such a case, however, the following new problems occur. In the polling method of collecting the node information at a short period, if the NMS manages many nodes, a processing load of the NMS increases. If a collecting period of the node information of the NMS is shortened in a network of a large scale, a load on the NMS further increases and it is difficult to collect the node information. Also in the active program method, similarly, when a node information collecting period in the network of a large scale is shortened, a load on the NMS increases.